1. Technical Field Of The Invention
The present invention relates to improvements of a terminal crimping method for electrically connecting an electric terminal to a flat circuit body by penetrating a point portions of at least a pair of piercing parts erected from opposite side edges of a flat part of an electrically connecting terminal through a cover and a conductor of the flat circuit body and bending the point portions so as to approach each other, and a terminal crimping apparatus therefor.
2. Related Art
FIG. 11 shows the flat circuit body 1 and the electrically connecting terminal 2 to be connected thereto.
The flat circuit body 1 is an FFC (Flexible Flat Cable) in which a plurality of lengthy and thin sheet like conductors 4 are covered with a thin film isolating cover 5 and are finished up as a generally flexible band-like cable. The conductors 4 may be formed by pattern-printing or attaching conductive material previously formed as a tape onto an isolating sheet.
The electrically connecting terminal 2 comprises a flat part 6, a plurality of pairs of piercing parts 7, 8 erected from opposite side edges of the flat part 6 at the base side, and a terminal connecting part (not shown) formed at the distal end side of the flat part 6 and is integrally formed by pressing a metal plate.
The terminal connecting part (not shown) is for connecting another connecting terminal, and may be formed, for example, as a female or male structure to be placed in a connector housing.
FIGS. 12 and 13 show a related terminal crimping apparatus 10 generally in cross section for crimping the electrically connecting terminal 2 to the flat circuit body 1.
The terminal crimping apparatus 10 is provided with a lower crimper 11 for supporting the lower side of the flat part 6 of the electrically connecting terminal 2, and an upper crimper 13 arranged above and opposite to the lower crimper 11 and having molding faces 13a, 13b for bending the point portions of the piercing parts 7, 8 standing oppositely each other.
Crimping of the electrically connecting terminal 2 in the terminal crimping apparatus 10 is, as shown in FIG. 12, carried out at first by arranging the flat circuit body 1 between the electrically connecting terminal 2 placed on the lower crimper 11 and the upper crimper 13, and subsequently by moving down the upper crimper 13 as indicated by an arrow A so that the lower crimper 11 and the upper crimper 13 come close to each other.
Then, the piercing parts 7, 8 of the electrically connecting terminal 2 penetrate through the flat circuit body 1, and as shown in FIG. 13, the point potions of the piercing parts 7, 8 projected from the flat circuit body 1 on the upper side thereof are bent back toward the flat circuit body 1, thereby crimping the electrically connecting terminal 2 to the flat circuit body 1.
FIG. 14 shows in cross section the piercing parts 7, 8 of the electrically connecting terminal 2 crimped to the flat circuit body 1 by the terminal crimping apparatus 10.
The piercing parts 7, 8 penetrates through the conductor 4 and the isolating cover 5 of the flat circuit body 1 for electrically connection with the electric conductor 4. Further, the point portion of the piercing parts 7, 8 are bent back toward the flat circuit body 1 until the point portion pierces the flat circuit body 1 again, thereby crimping the electrically connecting terminal 2 to the flat circuit body 1.
However, according to the related terminal crimping apparatus 10, as shown in FIG. 12, in case the crimping operation is started with the electrically connecting terminal 2 and the flat circuit body 1 being in order set on the lower crimper 11, the flat circuit body 1 may, for example, slightly displace in the face direction (back and forth, right and left in FIG. 12) or vibrate. In this case, the electrically connecting terminal 2 having the point portions of the piercing parts 7, 8 being in contact with the flat circuit body 1 is probably displaced from position as shown in FIG. 15.
A problem is involved that if both crimpers 11, 13 are brought close to each other in above case, the piercing parts 7, 8 maybe buckled as shown in FIG. 16 to generate bad crimping.
It is accordingly an object of the invention to eliminate the above mentioned problems and to provide a terminal crimping method and an apparatus therefor which are least to cause inferior crimping owing to buckling of the piercing parts and may operate crimping of high quality.
The object of the invention may be attained by a terminal crimping method of electrically connecting an electrically terminal having a pair of piercing parts and a flat part to a flat circuit body including a cover and a conductor therein by a terminal crimping apparatus including an upper crimper, a lower crimper, a terminal guide and a circuit body holder the terminal crimping method comprising the steps of:
placing the electrically connecting terminal on the lower crimper;
guiding the pair of piercing parts by the terminal guide relatively movable along outer sides of the pair of piercing parts;
elastically holding the flat circuit body disposed between the upper crimper and the lower crimper by the terminal guide and the circuit body holder;
relatively moving the upper crimper toward the lower crimper;
piercing the cover and the conductor by point portions of the pair of piercing parts; and
bending the point portions of the pair of piercing parts so as to approach each other by a molding face of the upper crimper.
Further, the object of the invention may be attained by a terminal crimping apparatus for electrically connecting an electrically connecting terminal having a pair of piercing parts and a flat part to a flat circuit body having a cover and a conductor therein, the terminal crimping apparatus comprising:
a lower crimper which supports a lower side of the flat part;
an upper crimper arranged above to the lower crimper having a molding surface for bending point portions of the pair of piercing parts by relatively moving toward the lower crimper;
a terminal guide movable along outer sides of the pair of piercing parts for guiding the pair of piercing parts; and
a circuit body holder arranged above and opposite to the terminal guide for elastically holding the flat circuit body in cooperation with the terminal guides during the upper crimper moves toward the lower crimper.
According to the above mentioned structure, while the upper crimper is relatively moved toward the lower crimper to penetrate, at the point portions, the piercing parts of the electrically connecting terminal into the flat circuit body and deform the same by bending toward each other, the flat circuit body is sandwiched between the circuit body holders and the terminal guides arranged as being movable along and relative to the outer side of the piercing portions, and at the same time the piercing parts of the electrically connecting terminal are prevented from falling by the terminal guides.
Further, in the process for crimping the electrically connecting terminal to the flat circuit body, when the piercing parts penetrate into the flat circuit body, the flat circuit body is prevented from slight displacement in the face direction and from vibrations while the portions to be penetrated are maintained as being tensed. The positional relationship with the point portions of the piercing parts is stabilized, so that the piercing parts may penetrate into the flat circuit body under a balanced condition.
Further, the piercing parts of the electrically connecting terminal controlled from falling by the terminal guides may be deformed as being bent toward each other without being deviation.
Therefore, according to the terminal crimping method and the apparatus therefor, inferior crimping owing to buckling of the piercing parts is least to occur, and the crimping of high quality may be carried out.
Preferably, by means of the molding face, one of the pair of piercing parts penetrating at the point portion of said one through the flat circuit body is bent back toward said flat part of the electrically connecting terminal to again penetrate through the conductor by means of the molding face of the upper crimper, while the point portion of the other piercing part is laid upon said one of the point parts such that said one is urged toward said flat part.
In this case, when the pair of piercing parts penetrating the flat circuit body are bent back, since one of the point portions is laid upon the other point portion, the pair of piercing parts may have occupation width enough with width occupied by one of the other piercing parts. Thus, the width occupied by one electrically connecting terminal on the flat circuit body may be largely reduced, and the electric conductors may be arranged with a narrower pitch provided therebetween on the flat circuit body.
Further, since the point portion of one piercing part which penetrates the flat circuit body and then is in advance bent back, again pierces the conductor of the flat circuit body and is held down by the point portion of the other pierce part, the one piercing part may be prevented from spring back by the point portions of the other piercing part.
Therefore, fixation of the electrically connecting terminal to the flat circuit body is not loosened by spring back, and reliability to electric conductivity of the flat circuit body may be heightened.